Communication system and method for communication for a motor vehicle

Abstract

A communication system intended for use in a motor vehicle includes a plurality of devices (26, 28), a transmission channel (32) that connects the plurality of devices (26, 28) to one another, and a signal source (30) coupled to the transmission channel (32). Each of the devices (26, 28) includes a control unit (36) configured for evaluating signals of the transmission channel (32), and at least two coupling units (38, 40) configured for connecting and disconnecting the particular device (26, 28) to/from the transmission channel (32). The control units (36) of the devices (26, 28) are configured for causing the coupling units (38, 40), at a certain point in time, in each case to connect no more than one of the devices (26, 28) to the transmission channel (32), and to disconnect the other of the devices (26, 28) from the transmission channel (32).

The invention claimed is: 
     
       1. A communication system ( 14 ) for a motor vehicle ( 10 ), having:
 a plurality of control devices ( 26 ,  28 ) for determining a condition of the motor vehicle based on a signal; 
 a transmission channel ( 32 ) that connects the plurality of control devices ( 26 ,  28 ) to one another; and 
 a source ( 30 ) for the signal separate from the control devices ( 26 ,  28 ) and coupled to the transmission channel ( 32 ), wherein each of the control devices ( 26 ,  28 ) includes: 
 a control unit ( 36 ) that is configured for evaluating signals of the transmission channel ( 32 ); and 
 at least two coupling units ( 38 ,  40 ) that are configured for selectively connecting a particular control device ( 26 ,  28 ) to the transmission channel ( 32 ) for enabling the control devices ( 26 ,  28 ) to monitor the signal source ( 30 ) in a redundant manner, wherein the control units ( 36 ) of the control devices ( 26 ,  28 ) are configured for causing the coupling units ( 38 ,  40 ), at a certain point in time, to connect no more than one of the control devices ( 26 ,  28 ) to the transmission channel ( 32 ), and to disconnect another control device of the plurality of control devices ( 26 ,  28 ) from the transmission channel ( 32 ). 
 
     
     
       2. The communication system ( 14 ) according to  claim 1 , wherein each of the control devices ( 26 ,  28 ) also includes a monitoring unit ( 42 ) that is coupled to a particular control unit ( 36 ) and configured for recognizing an error state of the particular control device ( 26 ,  28 ) and signaling to the particular control unit ( 36 ) of the control device ( 26 ,  28 ), wherein the control units ( 36 ) of the control devices ( 26 ,  28 ) are configured to cause, at the certain point in time, particular coupling units ( 38 ,  40 ) of the particular control device ( 26 ,  28 ), for which the error state has been recognized, to disconnect the particular control device ( 26 ,  28 ) from the transmission channel ( 32 ). 
     
     
       3. The communication system ( 14 ) according to  claim 1 , wherein the control unit ( 36 ) and/or a monitoring unit ( 42 ) contained in one control device of the plurality of control devices ( 26 ,  28 ) are/is configured to cause the coupling units ( 38 ,  40 ) of the one control device ( 26 ,  28 ) to connect the one control device ( 26 ,  28 ) to the transmission channel ( 32 ) or disconnect the one control device ( 26 ,  28 ) from the transmission channel ( 32 ). 
     
     
       4. The communication system ( 14 ) according to  claim 1 , wherein the plurality of control devices ( 26 ,  28 ) are connected in parallel to one another via the transmission channel ( 32 ). 
     
     
       5. The communication system ( 14 ) according to  claim 1 , wherein the signal source ( 30 ) includes a switchable power source that is supplied with power by only the control device ( 26 ,  28 ) currently connected to the signal source ( 30 ) via the transmission channel ( 32 ). 
     
     
       6. The communication system ( 14 ) according to  claim 1 , wherein the plurality of control devices ( 26 ,  28 ) are configured for determining the no more than one control device ( 26 ,  28 ) by communication among the plurality of control devices ( 26 ,  28 ). 
     
     
       7. The communication system ( 14 ) according to  claim 1 , wherein the at least two coupling units ( 38 ,  40 ) of each control device ( 26 ,  28 ) include a high-side coupling unit ( 38 ) and a low-side coupling unit ( 40 ). 
     
     
       8. The communication system ( 14 ) according to  claim 1 , wherein each of the control devices ( 26 ,  28 ) also includes a signal conditioning unit ( 44 ) that is configured for receiving and providing the signals of the transmission channel ( 32 ) to the particular control unit ( 36 ) of the control device ( 26 ,  28 ) in a defined format. 
     
     
       9. The communication system according to  claim 1 , wherein the signal source is a single wheel speed sensor for producing a wheel speed signal and the control devices cooperate to monitor functionality of the single wheel speed sensor in a redundant manner. 
     
     
       10. A method for communication between a plurality of control devices ( 26 ,  28 ) in a motor vehicle ( 10 ), wherein the plurality of control devices ( 26 ,  28 ) are situated in the motor vehicle ( 10 ) and are connected to one another via a transmission channel ( 32 ), wherein the transmission channel ( 32 ) is coupled to a signal source ( 30 ) separate from the control devices ( 26 ,  28 ), and wherein the method comprises:
 operating control units ( 36 ) of the control devices ( 26 ,  28 ) such that one of the control devices ( 26 ,  28 ) is connected to the transmission channel ( 32 ) via at least two coupling units ( 38 ,  40 ) of the one control device ( 26 ,  28 ); 
 operating the control units ( 36 ) of the control devices ( 26 ,  28 ) to disconnect the other of the control devices ( 26 ,  28 ) from the transmission channel ( 32 ) via at least two coupling units ( 38 ,  40 ) of the other control device ( 26 ,  28 ); and 
 operating the control unit ( 36 ) of the one control device ( 26 ,  28 ), which is connected to the transmission channel ( 32 ), to evaluate signals of the transmission channel ( 32 ) from the signal source ( 30 ) while another control device ( 26 ,  28 ) of the plurality of control devices is used as a redundant evaluator of signals of the transmission channel ( 32 ) from the signal source ( 30 ). 
 
     
     
       11. A motor vehicle ( 10 ) that includes a communication system ( 14 ) according to  claim 1 .